Published in Report: Understanding and Modeling Vortical Flows to Improve the Technology Readiness Level for Military Aircraft, October 1, 2009, pages 1-26. Chapter 29. Copyright © 2009 NATO Research and Technology Organisation. The definitive version is available at http://www.rta.nato.int/Pubs/RDP.asp?RDP=RTO-TR-AVT-113.
NOTE: At the time of publication, the author Russell M. Cummings was on sabbatical leave from Cal Poly.
It has been observed that delta wings placed in a transonic freestream can experience a sudden movement of the vortex breakdown location as the angle of incidence is increased. The chapter reports on the use Computational Fluid Dynamics (CFD) to examine this behaviour in detail. The study shows that a shock-vortex interaction is responsible. The balance of the vortex strength and axial flow, and the shock strength, is examined to provide an explanation of the sensitivity of the breakdown location. Limited experimental data is available to supplement the CFD results in certain key respects, and the ideal synergy between CFD and experiments for this problem is considered.